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Your fuse box is one of the most important parts of your home’s electrics. But most homeowners never think about it until something goes wrong.

In this guide, we explain the warning signs that mean your fuse box needs replacing, how much a replacement costs in London, and what to expect on the day.

Sky Electrical is a NICEIC-approved contractor based in Twickenham. We replace fuse boxes and consumer units for homeowners across London and Surrey.

What Is the Difference Between a Fuse Box and a Consumer Unit?

The terms ‘fuse box’ and ‘consumer unit’ refer to the same thing. This is the box that controls and distributes electricity around your home. However, they are different in terms of age and safety.

Older homes have traditional fuse boxes. These use wire fuses that blow when there is a fault. Modern homes have consumer units. These use circuit breakers and RCD (residual current device) protection, which are far safer.

If your property still has an old fuse box with ceramic wire fuses or a wooden back, it is almost certainly time for an upgrade.

 

7 Signs Your Fuse Box Needs Replacing

1. Your fuse box is more than 25 years old

Electrical standards change over time. A fuse box installed before 2000 may not meet current regulations. It may lack the RCD protection that is now standard in all new consumer units.

2. You have a metal or wooden fuse board

Old-style metal or wooden fuse boards with ceramic fuse holders are no longer compliant with modern wiring regulations. They offer much less protection than a modern consumer unit.

3. Fuses keep blowing or breakers keep tripping

If a single fuse blows or breaker trips occasionally, that can be normal. But if it happens often, especially on multiple circuits; it suggests something is wrong. This could mean your wiring is overloaded or there is a fault that needs investigating.

4. You are having electrical work done

If you are adding a new kitchen, a home extension, or an EV charger, your electrician may recommend upgrading your consumer unit at the same time. This is often more cost-effective than doing it separately later.

5. Your home has received an unsatisfactory EICR

An EICR inspection often flags old consumer units as the main reason for failing. If your property receives an unsatisfactory EICR report, a consumer unit upgrade is often the remedy.

6. You are buying or selling a property

Mortgage lenders and insurers may require an up-to-date EICR. If the survey or EICR flags the fuse box, upgrading it before exchange can speed up the sale.

7. You notice signs of burning or scorching

Scorch marks around your fuse box, a burning smell, or discolouration around sockets are signs of a potentially dangerous fault. Switch off the main switch and call a qualified electrician immediately.

 

Consumer Unit Replacement Cost in London (2026)

The cost of replacing a fuse box in London is higher than the UK national average. A consumer unit (fuse box) upgrade typically costs from £650-£1,300 (exc. VAT). The main factors that affect the price are the size of your property and the number of circuits.

Please note that prices vary. This price range is a rough guide and is dependant on specific requirements, and the amount of fuse boards.

Sky Electrical offers 0% APR finance on all electrical work, so you can spread the cost with monthly payments and no interest charges.

Please contact our friendly team to get a free site survey and quote.

 

What Happens During a Consumer Unit Replacement?

Here is what to expect on the day:

  1. The electrician will survey your current fuse box and circuits before starting any work.
  2. The power to your home will need to be switched off. This usually takes between 4 and 10 hours, depending on the size of your property.
  3. The old fuse box is removed and the new consumer unit is installed. All circuits are reconnected, labelled, and tested.
  4. The electrician carries out a series of electrical tests to confirm everything is safe and working correctly.
  5. You receive an Electrical Installation Certificate. This is a legal document. Keep it safe.

 

You will need to be home for the duration of the job. Plan for the power to be off for most of the day. We recommend having somewhere warm to sit and making sure any food in your fridge or freezer is covered.

 

Is It a Legal Requirement to Replace Your Fuse Box?

There is no law that says you must upgrade your fuse box by a specific date if you are an owner-occupier. However, your home insurance policy may require you to have up-to-date wiring.

For landlords, the rules are stricter. An EICR must be carried out every five years. An old fuse box without RCD protection will almost always result in a C2 fault code, which means you are legally required to carry out remedial work within 28 days.

Even if there is no legal obligation, upgrading an old fuse board significantly improves the safety of your home and its occupants.

 

Are There Grants for a Free Fuse Box Replacement in the UK?

In some cases, households on low incomes or certain benefits may be eligible for free or subsidised electrical work through the government’s Energy Company Obligation (ECO4) scheme. This scheme is administered through energy companies such as British Gas, E.ON, and Octopus Energy.

However, these grants are means-tested and have specific eligibility requirements. Not all properties or circumstances qualify. We recommend checking directly with your energy supplier or visiting the government’s ECO4 website for the most up-to-date eligibility criteria.

 

Fuse Box Replacement in London and Surrey

Sky Electrical replaces fuse boxes and consumer units across Surrey, South-West London and the surrounding areas. We work in residential properties, HMOs, and commercial premises.

Our qualified electricians are based in Twickenham and cover Richmond, Kingston, Wimbledon, Wandsworth, Esher, Cobham, Guildford, and Berkshire.

Every consumer unit replacement comes with:

 

Frequently Asked Questions

How long does a fuse box replacement take?

Most residential fuse box replacements take between four and eight hours. Larger properties with more circuits take longer. We will give you an accurate estimate during your free site survey.

Can I stay in my home during the replacement?

Yes, but the power will be off for most of the day. You will not have lighting, heating, or kitchen appliances during the work. We always try to complete the job in one day so your disruption is minimal.

Do I need a new fuse box if I’m getting an EV charger installed?

Not always. Your electrician will check whether your existing consumer unit can support the additional load. In some cases, an upgrade is needed, particularly if your current fuse board is old or already running at capacity.

What is an RCD and why does my consumer unit need one?

An RCD, or Residual Current Device, is a safety device that cuts off the power in milliseconds if it detects a fault. It protects against electric shocks and reduces the risk of electrical fires. All new consumer units must include RCD protection under the 18th Edition Wiring Regulations (BS 7671).

How do I know if my fuse box is old?

Signs include ceramic fuse holders with wire fuses, a wooden back, no trip switches (just fuses), or an overall appearance that looks 20+ years old. If you are unsure, a qualified electrician can inspect it and advise you.

 

Need a fuse box replacement in London or Surrey? Contact Sky Electrical for a free, no-obligation quote. We cover London, Richmond, Kingston, Wimbledon, Twickenham, and other surrounding areas.

Call 020 8894 1799 or visit our booking page,  to book a free site survey and get a quote.